钢水钙基脱硫剂的应用探讨

在钢铁市场面临激烈竞争的形势下,用户对产品质量,品种的要求不断提高。深脱硫已经成为提高钢质量、扩大品种和开拓钢材市场的重要手段。针对钢水钙基脱硫剂的文献研究中,并对其学者的文献和观点进行归纳和总结,找出提高钢水快速脱硫的途径。     

A comprehensive review on oxygen transport membranes: Development history,current status,and future directions

In view of its important role as raw materials in various energy and environment fields, pure oxygen has been widely required. The present cryogenic distillation, polymeric membrane and pressure swing adsorption (PSA) air separation methods are either energy-intensive or producing non-high purity oxygen. The comparative analysis of the inorganic dense ceramic-based oxygen transport membranes (OTMs) with these traditional oxygen production technologies and the H₂/O₂ production by electrolysis of water shows irreplaceable advantages. The oxygen transport mechanism has been elaborated further to reveal the theoretical basis for the development of OTMs. The dual-phase membranes that have been widely studied are divided into three types according to the conduction paths of oxygen ions and electrons. Based on a review of the different types of OTM materials experienced in the past 30 years, its applications such as oxygen-enriched combustion involving H₂ and membrane reactors have been discussed. Finally, challenges and future directions are analyzed according to potential industrial design directions and competitive technologies of OTMs.     

萤石浮选捕收剂研究进展

萤石捕收剂可分羧酸类、生物脂类、两性捕收剂 、复合捕收剂、烷基膦酸和烷基硫酸(烷基磺酸)等五类,其中绝大部分属化工厂副产品。羧酸类(油酸或油酸盐)仍然是萤石浮选的主要捕收剂。使用两性捕收剂能改善萤石-方解石分离的选择性,而生物脂类则可有效排除萤石精矿小的二氧化硅。     

凝胶挤出流延聚氟乙烯薄膜的研究

介绍了一种适合聚氟乙烯薄膜生产制造的新工艺——凝胶挤出流延法。该工艺克服了聚氟乙烯自身结构特性给成型带来的困难，得到的薄膜产品具有耐候性强、强度高、透光率大等优点，并有很好的应用前景。此外还系统讨论了树脂结构、潜溶剂及加工条件对薄膜制品的影响。     

一种耐低温型捕收剂在萤石浮选中的应用

本文通过对不饱和脂肪酸进行磺化改性,然后与不饱和脂肪酸复配(两者质量比为1∶2)混合,再加入表面活性剂以及助剂混合得到一种耐低温型捕收剂,其中含有羧基、磺酸基等基团,将其用于萤石矿浮选,其浮选效果优于油酸、妥尔油和氧化石蜡皂(731)。针对河北某矿业公司萤石矿石性质,进行了详细的条件试验,最终确定一粗一扫五精浮选工艺流程,在矿浆温度为10~15℃条件下,以碳酸钠为调整剂,水玻璃为脉石抑制剂,闭路试验可获得萤石精矿Ca F2品位为97.26%、回收率为81.11%的浮选指标,具有较好的推广应用价值     

柠檬酸对萤石和方解石的抑制效果研究

通过单矿物浮选试验、人工混合矿试验、Zeta电位测定、接触角测试及X射线光电子能谱(XPS)测试分析,考察了柠檬酸对萤石和方解石在浮选中的作用机理。结果表明,在油酸钠体系下,柠檬酸对萤石的抑制效果强于方解石,柠檬酸抑制两种矿物受pH值的影响较小。对于萤石和方解石的混合矿,随着pH值的升高,萤石精矿的品位和回收率开始下降。Zeta电位、接触角测试及XPS分析结果表明,萤石比方解石表面电位高,Ca 2p轨道的电子结合能大,更容易与柠檬酸结合。柠檬酸作用后,萤石比方解石电位负移大,接触角降低明显,Ca 2p轨道中Ca-COOR的相对含量占比多。萤石与方解石混合时,随着矿浆pH值的升高,Ca 2p轨道中Ca-CO₃的相对含量占比逐渐升高。     

稀土尾矿中萤石、重晶石浮选分离研究

针对某稀土选矿尾矿中萤石与重晶石品位较低、单体解离度较好的特征,通过试验研究,确定了萤石、重晶石混合浮选—萤石、重晶石浮选分离—重晶石粗精矿反浮选的浮选工艺流程对其中的萤石、重晶石进行回收。中国地质科学院矿产综合利用研究所自行研制的浮选药剂EMLB-1与EMLY-1在本研究中得到了很好的应用,其中EMLB-1可有效的对萤石、重晶石进行捕收,EMLY-1在萤石、重晶石浮选分离中对重晶石抑制效果明显;试验在重晶石粗精矿反浮选中,在抑制重晶石的前提下,采用NaF选择性的活化脉石矿物,大大的增强了反浮选的效果。最终试验获得了CaF2品位97.33%、含BaSO40.03%、回收率74.40%的萤石精矿和BaSO4品位90.42%、含CaF22.65%、回收率90.12%的重晶石精矿,使得该尾矿中的萤石与重晶石得到了有效的分离。     

某低品位萤石矿浮选工艺改进实践

某萤石选厂目前的工艺已不能满足生产的需要,经过试验,将中矿流程进行改进,新的生产工艺可使萤石品位由88.52%提高到92.64%,回收率由原来的75.56%提高到86.78%,为企业增加了经济效益.      

Optically stimulated luminescence: Searching for new dosimetric materials

Optically stimulated luminescence (OSL) is increasingly being used as a dosimetric technique in various fields such as medical, environmental and space dosimetry, and sediment and archaeological dating. Nevertheless few compounds are suitable as OSL materials. In this work, a survey was made of various insulators, searching for candidates for new OSL dosimeters. Natural and synthetic crystals and glasses from numerous sources are included. Luminescence was stimulated with blue LEDs (470 nm) and with IR laser (830 nm) provided by an automatic reader. Irradiation was performed with a ⁹⁰Sr/⁹⁰Y beta source, and the emitted light was measured with a photomultiplier tube, protected with suitable optical filters. Thermoluminescence (TL) of the samples was also measured, with the same equipment, to evaluate the thermal and optical stability of the defects related to OSL and TL. Among the various investigated materials, Al₂O₃:Cr, Mg, Fe, MgAl₂O₄ spinels, Mg₂SiO₄:Tb, and natural fluorite show potential as OSL dosimeters. Some materials, as barium aluminoborate glasses, although showing intense OSL signals, present a high fading at room temperature. In that situation the OSL signal is related to low temperature TL peaks that also fade at room temperature. None of the investigated materials was specially prepared to be used as an OSL dosimeter, which means that work can be done, mainly in the impurity nature and content, in order to improve OSL signals and to overcome some of the shortcomings that were noticed.     

Chemical and microstructural characterisation of HfO2-Y2O3 ceramics with high amount of Y2O3 (33, 40 and 50 mol. %) manufactured using spark plasma sintering

Hafnia based ceramics are potential promising candidates to be used as thermal barrier coatings (TBC) for applications in the field of propulsion. In this study, Spark Plasma Sintering (SPS) of fully stabilised hafnia with yttrium oxide (yttria) was investigated to provide a better understanding of the effect of manufacturing parameters, on the crystallography, chemistry and microstructure of the material. Several hafnia powders, containing different amounts of yttria (33 mol. %, 40 mol. % or 50 mol. %), were sintered by SPS at different temperature levels ranging from 1600 °C to 1850 °C. On these materials, X-ray diffraction patterns associated with scanning electron micrographs have highlighted the influence of both the sintering temperature and the amount of yttria on the final composition, the lattice parameter and the microstructure of hafnia-based materials. In the end, it is established that, for all quantities of yttrium employed, the main phase is Y₂Hf₂O₇ with very high densification levels.